2

我想在 Delphi XE5 中创建一个三角网格结构。

主 TMyMesh 类具有通用 TObjectLists 来保存顶点、面等的列表。

假设我必须为网格的每个面计算一些东西。我可以让 TMyMesh 类处理这个：

TMyVertex=class(TComponent)
  Vertex: TPoint3D;
  //other fields and methods
end;

TMyTriangleFace=class(TComponent)
  Vertices: Array [0..2] of Integer;
  //other fields and methods
end;

TMyMesh=class(TComponent)
  ListOfVertices: TObjectList<TMyVertex>;
  ListOfTriangleFaces: TObjectList<TMyTriangleFace>;
  procedure CreateListOfTriangleFaces;
  procedure DoSomethingWithTheFace(const FaceNumber: Integer);
  procedure DoSomethingWithAllFaces;
end;

procedure TMyMesh.CreateListOfTriangleFaces;
begin
  for i := 0 to NumberOfTriangleFaces-1 do
  begin
    ListOfTriangleFaces.Add(TMyTraingleFace.Add(nil));
  end;
end;

procedure TMyMesh.DoSomethingWithTheFace(const AFaceNumber: Integer);
begin
  AVertex:=ListOfVertices[ListOfFaces[AFaceNumber].Vertices[0]];
  //do something
end;

procedure TMyMesh.DoSomethingWithAllFaces;
begin
  for i := 0 to ListOfFaces.Count-1 do
  begin
    DoSomethingWithTheFace(i);
  end;
end;

或者我可以将它委托给 TMyTriangleFace 类：

TMyVertex=class(TComponent)
  Vertex: TPoint3D;
  //other fields and methods
end;

TMyTriangleFace=class(TComponent)
  Vertices: Array [0..2] of Integer;
  procedure DoSomethingWithTheFace;
  //other fields and methods
end;

TMyMesh=class(TComponent)
  ListOfVertices: TObjectList<TMyVertex>;
  ListOfTriangleFaces: TObjectList<TMyTriangleFace>;
  procedure CreateListOfTriangleFaces;
  procedure DoSomethingWithAllFaces;
end;

procedure TMyTriangleFace.DoSomethingWithTheFace;
begin
  AVertex:=TMyMesh(Owner).ListOfVertices[Vertices[0]];
  //do something
end;

procedure TMyMesh.CreateListOfTriangleFaces;
begin
  for i := 0 to NumberOfTriangleFaces-1 do
  begin
    ListOfTriangleFaces.Add(TMyTraingleFace.Add(Self));
  end;
end;

procedure TMyMesh.DoSomethingWithAllFaces;
begin
  for i := 0 to ListOfFaces.Count-1 do
  begin
    ListOfTriangleFaces[i].DoSomethingWithTheFace;
  end;
end;

在这种情况下，我需要让 TMyTriangleFace 类访问 ListOfVertices。我可以通过在过程 CreateListOfTriangleFaces 中将 TMyMesh 作为所有者传递来做到这一点。

在我的理解中，第二部分应该是更好的代码（得墨忒耳法则）。但是作为所有者传递 TMyMesh 可能不是那么好。

这样做的最佳做法是什么？也许这两种解决方案都朝着错误的方向发展，并且有更好的解决方案？

非常感谢你！

4

1 回答 1

3

Creating a new object for every vertex and triangle is very inefficient because of all the extra initialization overhead and individual memory allocations. Also access will be inefficient too due to data being sparse in memory (interleaved with objects headers Delphi creates?) and functions calls.

As David comments, it would be much faster to have everything in a single TMyMesh class with vertices and indices as array of records.

于 2014-03-05T20:11:12.680 回答